1. Field of the Invention
This invention relates to an apparatus for recording picture data and jump-destination-position index information for high-speed playback on a recording medium such as an optical disc.
2. Description of the Related Art
In some cases, picture data are recorded on a recording medium such as an optical disc. During high-speed playback of a certain type, picture data on a recording medium are skip-read so that only some of 1-frame-corresponding segments of the picture data are sequentially reproduced on a periodic jump basis. The high-speed playback is used in a search for a desired scene represented by the picture data.
It is known to record picture data and also index information on a recording medium. The index information represents jump destination positions on the recording medium. The index information is used for high-speed playback.
According to a conventional recording system, the frame-measured intervals between separate 1-frame-corresponding segments of picture data which will be sequentially reproduced during high-speed playback are independent of the degree of motion or change in pictures represented by the picture data. Therefore, during high-speed playback of a portion of the picture data which relates to a high degree of picture motion or change, successively reproduced pictures greatly differ from each other in contents. The great differences between the successively reproduced pictures are unsuitable to a search for a desired scene. On the other hand, during high-speed playback of a portion of the picture data which relates to a very low degree of picture motion or change, successively reproduced pictures remain approximately constant in contents. Thus, it takes a long time to find a desired scene.
It is an object of this invention to provide an improved recording apparatus.
A first aspect of this invention provides a recording apparatus comprising a compressive encoder for compressively encoding an input video signal into compression-resultant data whose amount is variable from frame to frame; first means for measuring an accumulative amount of the compression-resultant data generated by the compressive encoder; second means for generating information of a jump destination position when the accumulative amount measured by the first means reaches a predetermined amount; and third means for recording the compression-resultant data generated by the compressive encoder and the jump-destination-position information generated by the second means on a recording medium.
A second aspect of this invention is based on the first aspect thereof, and provides a recording apparatus further comprising fourth means for counting frames represented by the compression-resultant data; fifth means for generating information of a jump destination position when a number of frames counted by the fourth means reaches a predetermined number; and sixth means for recording the jump-destination-position information generated by the fifth means on the recording medium.
A third aspect of this invention is based on the first aspect thereof, and provides a recording apparatus further comprising fourth means for resetting the accumulative amount measured by the first means when the second means generates the jump-destination-position information.
A fourth aspect of this invention provides a recording apparatus comprising a compressive encoder for compressively encoding an input video signal into compression-resultant data, and generating a signal representing a motion in pictures represented by the compression-resultant data; first means for measuring an accumulative amount of the motion represented by the signal generated by the compressive encoder; second means for generating information of a jump destination position when the accumulative amount measured by the first means reaches a predetermined amount; and third means for recording the compression-resultant data generated by the compressive encoder and the jump-destination-position information generated by the second means on a recording medium.
A fifth aspect of this invention is based on the fourth aspect thereof, and provides a recording apparatus further comprising fourth means for counting frames represented by the compression-resultant data; fifth means for generating information of a jump destination position when a number of frames counted by the fourth means reaches a predetermined number; and sixth means for recording the jump-destination-position information generated by the fifth means on the recording medium.
A sixth aspect of this invention is based on the fourth aspect thereof, and provides a recording apparatus further comprising fourth means for resetting the accumulative amount measured by the first means when the second means generates the jump-destination-position information.